Waterborne basecoats, including metallic waterborne basecoats and chromatic/solid waterborne basecoats, have been used for vehicle refinishing. Existing basecoats are generally provided in various colors and metallic finishes. Waterborne basecoats, however, are subject to environmental challenges, such as changes in humidity and temperature, which may adversely affect orientation of the metallic pigments, overall appearance of the coating, color consistency and the ease of application.
Typically, in the industry, challenges in the overall appearance of waterborne metallic basecoats have been addressed by utilizing very tight quality control standards for the products, using color matching tools such as spectrophotometers, and utilizing alkali swellable waterborne acrylic dispersions. Moreover, environmental robustness is traditionally achieved by using reducers that evaporate at different rates to accommodate different humidity and temperature conditions. All of these challenges require manufacturers to provide multiple skus and product lines to accommodate these different challenges. It would, therefore, be useful, to have a robust rheology package and a simple set of components that could be used to achieve a wide variety of color and metallic finishes in view of known environmental challenges. Additionally, the use of alkali swellable waterborne acrylic dispersion as a resin negatively impacts physical properties of the vehicle refinish coating system including dry adhesion and wet adhesion retention.
Waterborne basecoats consist of toners/colorants made of various pigments (organic/inorganic/special effect) and pigment volume concentrations. Traditionally, basecoats use a single resin system across all pigment families which results in variations in physical properties (dry/wet adhesion) and coating properties (sandability of basecoat, hardness). Thus, it would be useful to build a basecoat system that comprises resins that can compensate for variations in pigments and pigment volume concentrations by simply changing the ratio of resins used in various toners/colorants.
Collectively, a rheology package that provides robust metallic orientation across multiple environments and a resin package that enables consistent properties of various toners/colorants will provide consistency to customers when using various basecoat colors at inconsistent environmental conditions globally. It will also provide improved physical properties including dry adhesion and wet adhesion due to presence of resins that can endure stresses that a vehicle refinish coating system is typically subject to instead of reliance on alkali swellable waterborne acrylic dispersions which easily undergo hydrolysis under extended exposure to high humidity.